The invention relates generally to electronic timing systems and controllers for controlling the cyclical operation of a number of individual section (I.S.) glassware-forming machines. More specifically, the invention relates to communication between a master I.S. machine controller and individual controllers associated with each component of the I.S. machine.
Electronic timing or control systems have been applied in the glassware-forming art to provide programmable means for operating complex individual section or I.S. glassware-forming machines. The glassware forming machine is typically comprised of a plurality of individual sections which are integrated into a single plural section machine fed by a single source of molten glass. The sections include functional components which are operated in synchronism in response to control signals received from an electronic timing or control system. For instance, the functional components of each section may include an electronic valve block, an electronic gob distributor and an electronic glassware transfer mechanism for conveying the newly formed glass from the section deadplate to a moving conveyor. Electronic timing is typically provided by programmable machine controllers which utilize a central processing unit and several satellite computer units associated with each I.S. machine section. The master control computer for the complete glassware-forming machine, as well as the individual control computers for each of the section components, must be capable of processing a variety of input and output data for controlling the function of each of these components, as well as data indicating the status of the operation of the components.
Several electronic I.S. machine control systems are known in the art. For instance, the patent to Hotmer, U.S. Pat. No. 4,369,052, discloses a forming supervisory control computer for controlling the operation of individual section glassware-forming machines. This reference describes a forming supervisory computer, a machine supervisory computer and individual section computers that are connected by serial input/output interface boards. The patent to Japenga et al., U.S. Pat. No. 4,641,269, shows a similar supervisory system in which a machine supervisory computer communicates with a number of local section computers through a multiplexer which conveys information to an appropriate section computer.
Another I.S. machine controller is produced by ESIA of France, known as the IS-Apilog, which includes a main controller and several machine interface controllers, as described in ESIA product description NTC/1220B/005/0/RP. Electronic information is communicated between the various components of the Apilog machine by way of several multi-conductor cables. The Apilog unit, as with the other units just discussed, requires the use of multi-conductor cables for electronic communication between the components of the unit. For instance, the Apilog device is disclosed as requiring the use of a 17 conductor cable connecting between each section control unit and a section relay box, and 35 conductor connecting cables between each section relay box and the main control cabinet.
The electronic timing and control systems for the I.S. glassware forming machines of the prior art have produced beneficial results in that a variety of control and information functions are now integrated into a single master or supervisory machine. However, these prior art I.S. machine controllers require the use of a multitude of electrical conductors and cables to transmit data to and from the master controller and the individual section component controllers. In many instances, these cables must run over long distances, often up to 200 feet among the farthest-most sections of an I.S. machine. Most I.S. machine control systems include a tangled array of electrical connectors and wires which present a variety of problems to the assembly and maintenance of an I.S. machine system. Moreover, a greater number of conductors or wires increases the cabling cost for a specific I.S. machine installation.
There is, therefore, a need for an I.S. electronic timing and control system which can significantly reduce the cabling requirements as well as the hardware costs associated with cables and connectors. There is also a need for an electronic timing system which is less expensive, more reliable and easier to trouble-shoot.